1. Field of the Invention
The present invention relates to an intermediate transfer body and an image forming apparatus.
2. Description of the Related Art
In an electrophotographic image forming apparatus is employed a method in which a toner image is obtained by developing an electrostatic latent image on an electrostatic latent image bearing member with a toner and the toner image is transferred to a recording medium to form the toner image on the recording medium. As a transfer method in an image forming apparatus is used a method in which a toner image formed on an electrostatic latent image bearing member is transferred to an intermediate transfer belt which bears and conveys a toner image transferred thereto, the toner image transferred to the intermediate transfer belt is electrostatically moved to a recording medium by a transfer section which faces the intermediate transfer belt with the recording medium interposed therebetween. A belt cleaning apparatus is arranged to remove a residual toner remaining on an outer peripheral surface of an intermediate transfer belt after transferring a toner image to a recording medium.
A blade type belt cleaning apparatus is widely used as a belt cleaning apparatus. The blade type belt cleaning apparatus is a belt cleaning apparatus in which a plate-like cleaning blade is abutted on a surface which bears a toner image of an intermediate transfer belt and a residual toner remaining on an outer peripheral surface of the intermediate transfer belt is scraped off. In such a blade type belt cleaning apparatus, the residual toner is sandwiched between the cleaning blade and the intermediate transfer belt, and the cleaning blade floats above the outer peripheral surface of the intermediate transfer belt. As a result, poor cleaning may occur.
To overcome those problems, Japanese Unexamined Patent Publication JP-A 2001-125449 discloses an image forming apparatus equipped with an intermediate transfer belt which is an endless belt member, having stepped portions extending in parallel with a width direction thereof provided on the outer peripheral surface thereof.
In recent years, an intermediate transfer belt comprising a base material comprising polyimide, and an elastic layer formed on the surface of the base material is being used in an electrophotographic image forming apparatus in order to improve a toner image bearing ability of an intermediate transfer belt and transferability of a toner image to a recording medium.
In the case where the intermediate transfer belt having an elastic layer is applied to the image forming apparatus disclosed in JP-A 11-95567 (1999), the cleaning blade abuts on the elastic layer on the outer peripheral surface of the intermediate transfer belt.
The image forming apparatus disclosed in JP-A 2001-125449 is constituted such that the stepped portions extending in parallel with the width direction of the intermediate transfer belt on which the cleaning blade abuts are provided on the outer peripheral surface thereof. Therefore, when the cleaning blade abuts on the stepped portions formed on the outer peripheral surface of the intermediate transfer belt, the cleaning belt catches on the stepped portions. As a result, not only the cleaning blade itself breaks and the residual toner scraped off from the intermediate transfer belt scatters, but reversal phenomenon that the cleaning blade rides up according to rotation of the intermediate transfer belt occurs, resulting in decrease in removal efficiency of the residual toner. The reversal phenomenon that the cleaning blade rides up remarkably occurs at a portion corresponding to ends in a width direction of the intermediate transfer belt among abutting portions of the cleaning blade to the intermediate transfer belt.
Furthermore, the elastic layer on the outer peripheral surface of the intermediate transfer belt easily undergoes elastic deformation. Therefore, the abutting portion of the cleaning blade, particularly ends in a width direction of the cleaning blade, excessively bites in the inside of the outer peripheral surface of the intermediate transfer belt from the outer peripheral surface thereof. Thus, when the abutting portion of the cleaning blade bites in the outer peripheral surface of the intermediate transfer belt, the reversal phenomenon of the cleaning blade occurs further remarkably, and removal efficiency of the residual toner is decreased.